Glow plug light not always going out

[MikeO]

Hi

It's only happened a couple of times (car in sig.). But...

Usually the Glow Plug light on the dash comes on for a couple of seconds and then goes out (as I assume it should.). But a few times recently I've turned the key, Glow plug light comes on, but does not seem to go out. Turn the ignition on and off a couple of times and then it seems to go out! Car / engine appears to be running fine otherwise. Not too worried but wondered if anyone might have a clue as to why this is?

Thanks.

 

[cocadave]

i get this every now and then, it shows up on my code reader as a glow plug fault

 

[MikeO]

i get this every now and then, it shows up on my code reader as a glow plug fault

So would I be right that you are not too worried either about this?

It's just that intermitent faults like this can be a swine to track down!

 

[flak monkey]

Probably a plug on its way out, how many miles has the car done?

 

[MikeO]

Believe it, or not, just under 38k in some 6+ years! Originally bought the car because I thought that I was going to carry on doing the stellar mileage that I used to do. But I now and have for some while now, worked from home. Funny how life frequently does not work out quite as you expected.

 

[flak monkey]

Could just be a dirty electrical connection on the glow plugs then. Try pulling the connectors off and putting them back on a few times and see if it sorts it.

David

 

[basssound]

i'm guessing either a faulty glow plug thats shorting internally or a faulty relay powering the golw plugs.
Also check the brake light bulbs, when you lose the whole the lot i.e. no brake lights at all, the glow plug stays on.

just a note - the top center brake lamp doesn't effect the glow plug, this may be working but the side brake lamps could be dead

 

[MikeO]

Thanks guys. This gives me a couple of things to try. Though as it doesn't always happen, could be a while before I can track the problem down.

 

[cocadave]

So would I be right that you are not too worried either about this?

It's just that intermitent faults like this can be a swine to track down!

I'm not too bothered about this as i check the fault logs quite regular, i used to get the fault codes probably 3 or 4 times a month but since changing the glow plugs about a year ago this stopped the codes from coming back up until about 4 months ago when they returned, i think its probably down to a faulty relay or something other than the plugs themselves, to be on the safe side i would invest in either a code reader of some sort or vagcom.

 

[MikeO]

cocadave

I've thought about a code reader before. Out of interest, what sort have you got? and would you recommend it? The only thing that makes me hesitate, is that a lot of the Vagcom error messages I've seen mentioned on the forum, appear "pretty generic". So not totally convinced how useful these devices actually are. I'd be interested in your comments, as one problem taking it to my local Ford garage for servicing (one problem with living in the middle of nowhere ... though they are pretty good) is that they don't have anything like the vagcom, so can't interrogate the electronicss.

 

[cocadave]

Mike

I can't seem to find an identical code reader to mine , however i have had a look and from what i have seen this is the same as mine except the exterior casing (mine is orange and a different shape)

http://cgi.ebay.co.uk/VAG-5053-DIAG...trkparms=65:12|66:2|39:1|72:1683|293:1|294:50

So far with it i have managed to reset the service interval and add a beep to the central locking funtion, as well as clearing a load of fault codes (glow plugs, egr valve,central control module)
as for the faults being a "bit generic" i suppose this is down to how common the fault is, i think it is good for pointing you in the right direction and if you need any explanation there are plenty of helpful folk on this site.

Just think, if you had one you could plug it in and see for youself why the glow plug light had come on in the past.

 

[MikeO]

cocadave

Thanks for your help. I've decided to buy the Gendan code reader as it appears to get decent reviews from people. I did think about going mad and buying the VAG-com software, but my laptop is on its last legs and I'm not sure if I will bother replacing it, as I've just built myself a new PC.

 

[oldman]

if your laptop has a serial port, keep it & rebuild as vanilla xp to use with vag-com.
get cable from ebay, get shareware vag-com and purchase the license file.

also, if all brake lights not working the glow plug flashes constantly and means switch is normally gone -> at least it does for a leon.

 

[MikeO]

oldman

Thanks for that. Something to think about. Though pretty sure it's the graphics chip that's on the way out, so not the easiest thing to replace in a laptop (possibly doo'able). Though already thinking of Windows 7 and an SSD to make my current PC "dual boot" with Vista. So many things to buy/do, just a matter of finding the money/time.

I'll see what the Gendan code reader says when it arrives, hopefully tomorrow.

I had come across comments on the forum about "flashing glow plug light"... but in my case, it just comes on when you turn the key and sometimes "just stays on". Car starts OK though and if you switch off and try again, light comes on and then goes off (as it should). Maybe (as already mentioned), a glow plug on the way out, or a lazy relay (my money would be on the latter).

We shall see.

Thanks again though.

 

[cocadave]

MikeO

I didn't realise that the glow plug light was coming on and staying on, this probably is the glow plugs taking time to heat up? does the light stay on forever?
Normaly if there is a fault the glow plug light will flash to tell you there is a problem, ive never heard of the light simply staying on.

oldman

how much does it cost to prchaasee the license file?

 

[MikeO]

cocadave

"I didn't realise that the glow plug light was coming on and staying on, this probably is the glow plugs taking time to heat up?"

Yep... This is what is happening. Though seems to happen at random. And only just started doing this (last week or so).

Even in the winter time, the glow plug light would normally be on for only a couple of seconds. In the summer months, especially when the engine is warm, it usually goes off almost straight away. But occasionally now it just stays on. Sometimes switching the ignition on and off (only to the first setting obviosly) will get it to go out. Other times I get fed up and just turn the engine over and it still seems to start OK. Odd!!!

I'll be interested to see what the code reader says when it turns up.

 

[oldman]

cocadave, think with the current exchange rate it is about £60-£70 as should be $99 direct from ross-tech.

an error code would certainly assist more with what is happening, however can it clear the fault code once issue is resolved?
the shareware of vag-com can also do that which is generall enough for most people, all i have.

 

[MikeO]

Code reader turns up this morning. So plug it in and have a quick look. Only appears to be one Engine code (so at least that's a relief):

17664/P1256 - Engine Coolant Temperature Circuit (G62): Open / Short to B+

Looked at Ross-tech wiki and found:

Possible Symptoms

1. Difficulties with starting a cold engine.
Diesel: an indication is extreme long time burning time of the glow indication light.
2. Starting the engine when engine is warmish or warm, idle rpm immediately is 1200 - 3000 rpm.
3. RPM at idle is irregular.
4. With all engine temperatures seldom idle rpm will vary between 900 - 1000 rpm.
With engine warm (90 °C) the engine temperature suddenly drops (70 °C) and slowly comes back to 90 °C.
5. Bad acceleration during warming up.

Now number one looks promising (IE. that appears to be my problem).

wiki goes on to say:

Possible Causes
Wiring and/or connections faulty
Engine Coolant Temperature Sensor (G62) faulty

Possible Solutions
Check wiring and connections
Check / Replace Engine Coolant Temperature Sensor (G62)

So... what to do now. Tempted to ignore it unless it gets any worse. One big give away, would be if the engine actually gets difficult to start (which it isn't at the moment).

Interesting...

 

[oldman]

seen No1 discussed a few time son here.
have a quick search and see what comes up. Can't recall what would be the fix or seriousness though

 

[cocadave]

mikeO

I would be inclined to reset the fault code and see if it comes back, if it does it is more than likely that the temperature sender unit will need replacing, this is really easy to do and there are guides about if you submit a search, just 1 thing to remember is make sure that the engine is flat cold.